Post ACO QA/procedures

Quality Assurance / Calibration
1

Hi All,

Could you guys please share the QA’s/procedures that you perform following an ACO calibration?

Thanks,

Ash

2

Hi Ash,

we have modified a calibration plate with 5 metal-sphere fiducials (diameter 1,5mm, stainless steel, one positioned at the center and the others along the two axes). We perform a system calibration after aligning this calibration plate carefully to the x-ray isocenter.

BR,

Marcus

3

Hi Marcus,

Thank you for your message. Using metal BBs—that’s a great idea. I am just curious if we should include an off-isocenter test (e.g., at ±10cm)?

Thanks,

Ash

4

we do the built in plate calibration, but then independently check the iso. Set up phantom (pentaguide or winston lutz) using sgrt surface, then cbct it, match and shift, then deliver MV beams as per daily or monthly procedure. Checks all isocentres match up. Yes off axis is worth doing, we do this with known shifts